Later that day, a Wall Street Journal article reported on what may be the logical next step: Fisker had "hired restructuring lawyers at Kirkland & Ellis LLP," it wrote, to help the company prepare for the possibility of a bankruptcy filing.

One deadline that would drive such a filing: Fisker faces an April 22 deadline for a payment to the U.S. Department of Energy on its low-interest loan under the Advanced Technology Vehicle Manufacturing program.

The DoE had originally awarded Fisker $529 million in loans in September 2009, but loan disbursements were frozen in 2011 after Fisker missed numerous deadlines for production of the Karma.

It had received a total of $192 million at that point.

While Fisker had downplayed last week's furlough--saying, in effect, that furloughs happen frequently in the auto industry--financial analysts considered it a serious and worrisome move.

The company hasn't built a single Karma range-extended luxury sport sedan since last summer, due to the banktuptcy of A123 Systems, its lithium-ion cell supplier.

That means it has no source of income. Tony Posawatz, the CEO it hired last August, has been meeting with potential investors and acquirers for several months now.

Not only was the outstanding U.S. government loan a major hurdle, but sources close to the negotiations say that the company proposed a large and costly restructuring plan that simply proved too expensive for the Chinese investors.

We contacted Fisker's Senior Director of Global Communications and PR, Roger Ormisher--twice, once on Thursday and once late Saturday--for comments on the speculation that Fisker is preparing to declare bankruptcy.

"We have no official comment to add at this stage," Ormisher told Green Car Reports.

"We promise to update once we have clearer information."

Because Fisker Automotive pledged its property and intellectual assets to the DoE as loan collateral, the U.S. government might end up holding those assets if Fisker does file for bankruptcy.

A Fisker insider tells us that the situation is "fast moving and changing constantly, with [many] stakeholders involved."

We'd expect some kind of announcement during the coming week or two, certainly before the April 22 deadline.